Compound cylinder press mechanism



March 10, 1959 JOSEPH G. YUHANIAK COMPOUND CYLINDERPRESS MECHANISM Filed March 30, 1956 M k K \K INVENTOR JOSEPH 6'. YUHA/V/AK BY 5m -5 ATTORNEXS United States Patent COMPOUND CYLINDER PRESS MECHANISM Joseph G. Yuhaniak, Salem, Ohio Application March 30, 1956, Serial No. 575,269 Claims. (Cl. 121- -38) The present invention relates to hydraulic power transmissions and more particularly to a compound cylinder press mechanism containing a plurality of pressure responsive elements for external power communication.

One object of 'the present invention is the provision of a compound cylinder press mechanism in which hydraulic pressure serves to actuate simultaneously a plurality of pistons contained within a common pressure chamber.

A second object of my invention is the provision of a compound cylinder press mechanism in which hydraulically actuated pistons contained within a common pressure chamber have interposed therebetween means to enable a reaction movement of one piston under power applied against another opposed piston.

A further object of my invention is to provide in a compound cylinder press mechanism including hydraulically actuated pistons contained Within a common pressure chamber, a yieldable connection between said pistons to enable a limited independent movement of each piston.

Other objects and advantages of my invention will be readily apparent from the following detailed description of a preferred embodiment thereof when taken in conjunction with the accompanying drawing, wherein:

Fig. 1 is a longitudinal vertical sectional view of a cylinder press mechanism constructed in accordance with the invention;

Fig. 2 is a transverse sectional view thereof taken substantially along the line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary horizontal sectional view of an alternative arrangement of resilient reaction means between the pistons disposed within the cylinder.

Briefly stated, the present invention contemplates a compound cylinder press mechanism containing a plurality of pistons yieldably united for simultaneous reciprocation under applied hydraulic pressure while each piston is capable of a limited independent movement through proper balancing of the applied hydraulic pressures.

Referring to the drawings, the operative mechanism of my invention is housed within a cylindrical casing 1 which provides apressure chamber when its ends are closed by cover members 2 and 3 suitably secured thereto, as for example by stud bolts (not shown). The cover members are provided with ports 4 and 5. through which fluid under pressure may be introduced into and/or dis-' charged from the interior chamber within the casing 1. Any appropriate hydraulic pressure system including adequate control and relief valves may be employed in 0011 nection herewith.-

A pair of pistons and 11 are disposed within the casing 1 for slidable reciprocation therein and have an outer diameter which is slightlysmaller than the inner 2 diameter of the casing 1. Piston rings 12, of conventional form, are disposed along the peripheral surface of the pistons 10 and 11 to serve as a fluid seal, preventing fluid leakage around the pistons.

A rod 20 is secured to the piston 10 centrally of the upper half thereof, a narrowed end portion 21 of the rod,

from the cylinder 1 through a bore 31 provided in the I cover member 3. An O-ring 32 seated in an annular groove 33 in the rod 20 enables independent rod movement through the piston 11 and seals the bore 30 against fluid leakage therethrough. A conventional sleeve bearing 35 and sealing gasket 36 are disposed within the bore 31 to guide the rod 20 in movement within said bore and to serve as a seal against fluid leakage. The outer-end of the rod 20 is threaded for connection to an object to be subject to pressure as to a mold member, not shown.

A rod 40 is secured to the piston 11 centrally of the lower half thereof and in vertical alinement with the rod 20. A narrowed end portion 41 of the rod, threaded at its extremity 42 passes through the body of the piston 11 and receives a locking nut 43 by means of which the piston 11 is forced against a shoulder 44 on the rod.

An O-ring 45 seated in an annular groove 46 provided in the end portion 41 of the rod seals the intermediate passage against fluid leakage therethrough. The rod 40 extends laterally of the cylinder 1 in spaced parallel relation to the rod 20 and projects from the cylinder 1 through a bore 50 provided in the cover member in vertical alinement with the bore 30. A conventional sleeve bearing 51 and sealing gasket 52 are disposed within the bore 50 to guide the rod 40 in its movement within said bore and to serve as a seal against fluid leakage.

The operation of the press is as follows: with the rods.

20 and 40 connected to work pieces, fluid under pressure is supplied through port 4 to the cylinder and operates against the piston 10 to move the rod 20 forward applying pressure to the work piece at the end of the rod. With no pressure at the end of the piston 11, this piston also moves forward but under a yielding pressure due to spring 61. When the resistance at the head of the piston 11 exceeds the tension of the spring 61, the pistons 10 and 11 are brought together, the head 42 seating in the opening 65. When this occurs the piston rods 20 vand 40 both move forward together, applying the full pressure of the hydraulic fluid ahead of the piston 10 to the work piece. When the pistons 10 and 11 are brought together,

port 4 by any conventional control valve.

In molding operations it is often essential that two molding elements be brought into engagement with the work in successive stages. This apparatus providedv means for doing this.

In the modification shown in Fig. 3, the spring 61 is replaced by pistons 72, connected by rods 74 to the piston 11. Pressure at the head of piston 10 acts to move the Patented Mar. 10, 1959 agave-res piston forward, but a lesser pressure will act on the hcads72 than on the piston 10 andtheref'ore a less pressure will be acting on the piston 11. When the piston rod 20 meets sufiicient resistance, the piston 10 no longer moves forward whereupon the pistons 72 move the piston 11 forward carrying the rod 40 forward and bringing maximum pressure upon the work piece at the end of the rod 40.

Matching sockets 60 are provided in the opposed surfaces ofpistons l and 11 on eachside of the vertical center line thereof and in spaced parallel relationship; Helical: springs 61: of any desired compressive strength are seated in the sockets and serve to-maintain a spacebetween. the pistons 10 and 11. If itis desired, tubular or sleeve guides (not shown) may be. placed aroundthe helicalsprings 61 to prevent. accidental displacement thereof. A detent collar 62 keyed to the piston rod 20 serves to limit diverging reaction movement between the pistons. Ill and 11 under the action. of the springs 61. A recess 65- is provided in the rodvside face of. the piston 10 for reception of the locking nut .43 projecting from the rear face of the piston 11 when the. pistons 10. and.

11 are so manipulated as; to be in abutting. relation. A

one-way check valve 66 is provided in the piston. 1t andis' secured in place by means of a vented screw plug 67 to permit escape from the space between the pistons. 10

and 11' any fluid which may accidentally enter such space during operation of the mechanisms, accumulations of which would impede proper piston manipulation. The outer ends of the rods 20 and 4-0 are threaded to admit attachment to mold elements (-not shown), the operation ofwh'ich' is to be controlled by the subject mechanism.

Instead of utilizing compression springs. 61 for reaction.

ject through suitable guideways 75 in the body of the piston 10. The rods 74 are secured to the opposed face of the piston 11 byany suitable means. Fluid pressure created upon the rear face of the piston 10 is communicated dilferentially through the pistons 72 to create a reaction movement of the piston 11 within the limits of outward travel of the'pistons 72.

It is thought that the operation of the press mechanism will be quite apparent from the foregoing. Briefly, the introduction of pressurized fluid into the casing 1 through either port 4 or 5 will occasion a direct driving impulse against the immediately adjacent piston or 11 to etiect its movement along the casing 1. Aslong as the opposite piston is free to move, it will do so as a result of the reaction movement of the helical springs interposed between the pistons. Where, however, there is created some impedance to the free movement of the opposite piston, as for example a hydraulic fluid pressure equivalent to the primary driving pressure is established behind the opposite piston or its rod controlled member meets eifective resistance to further advance, continued application of the primary driving pressure to the directly driven piston will move it into abutting relationship against the opposite piston by compression of the interposed helical springs. Thereafter the full effect of the primary driving pressure will he imparted equally against each piston and if it is sufiicient their simultaneous advance against the encountered resistance will be resumed. In the event the resistance exerted against the opposite piston is reduced or removed, the compression springs will expand outwards to their original length to move the opposed piston away from the driven piston which may be held stationary or may continue to advance.

And, of course, it follows that if at any time a blockirlg pressure is exerted against the opposed piston, it will The pistons 72 are provided with conventional peripheral sealing rings 73 and carry rods 74 which pro-- be moved closer to the primary driven piston, such. movemeut being permitted by compression of the helical springs 61.

To connect these principles to the mechanism illustrated in the drawing, the introduction of fluid pressure into the cylinder 1 through the port 4 will occasion a direct impulse upon the piston 10 driving it from right to left. Assuming the port 5 to be open and the rod to encounter no resistance, the opposite piston 11 will be moved simultaneously from right to left under the reaction movement imparted by the springs 61 and the pistons will maintain their spaced relation. If then the port 4 is closed and fluid under pressure is introduced into the cylinder 1 through the port 5, the expansion efiect of. the springs will be overcome so that the piston 11 will move from left to right until it engages the piston Ill. -Th'ereaf'ter', a reduction in the fluid pressure exerted. upon the. piston 11 will. permit it tomove from right to left, restoring the spaced relation with the piston 10, while a reduction in the fluid pressure exerted upon the piston 10 will permit it to move from left to right also restoring the spaced relation between the two pistons. Where a positive hydraulic driving pressure is maintained upon. the. pistonll and the hydraulic pressure directed againstthe piston-10 is released, the pistons are simultaneously moved from left to right to the limit of the'cylinder 1.

It will at once be obvious that various modifications in the sizes and configuration of the several elements incorporated in the mechanism will be dependent upon the nature of the Work to be effected thereby. Heavier castings will enable the use of increased hydraulic pressures, adapting the apparatus to heavier load manipulations' and/or" longer transmissions. Additionally, the: power transmission rods may be projected through oppo' v siteends of" the cylinders inthe event power transmission of this type is desired. Such modifications and altered arrangements are possible without departing. from the spirit of the invention or the scope of the appended claims.

What I claim is:

1. A compound cylinder mechanism for a molding. press and the like comprising a fluid tight housing, a plurality of pistons disposed within said housing for reciprocating movement therein under applied pressure and resilient means disposed between the pistons providing. a reaction movement of one piston under power applied against another piston, each of said pistons having a separate rod connected thereto and extending through the end of the housing and adapted to be connected to a work piece of the press.

2. A compound cylinder mechanism for a molding press and the like comprising a fluid tight housing, a plurality of pistons disposed within said housing for reciprocating movement therein under applied hydraulic pressure and resilient means disposed between the postons providing a reaction movement of one piston under power applied byanother piston, each of said pistons having a separate rod connected thereto and extending through the end of the housing and adapted to be connected'to awork piece of the press.

3'. A compound cylinder mechanism for a molding press and the like comprising a fluid-tight housing, a pair ofpistons' disposed within said housing, and yieldabl'y connected for simultaneous reciprocating, movement therein, means at each end of said housing to control the passage of pressurized hydraulic fluid therethrough. for actuation of said pistons, a separate piston rod secured to each of said pistons and projecting. from said" housing for communication exteriorly of. the housingof pressures exerted against said pistons, and resilient.means disposed between the pistons providing a reaction movement of one piston. under power applied against the connection to a work piece.

4. A compound cylinder mechanism as defined in claim 3 in which the piston rods project from the same end of the housing and are in spaced parallel relation.

5. In a compound cylinder mechanism of the type described for attachment to a molding press, the combination of a fluid-tight housing, a pair of normally spaced pistons disposed within said housing and yieldably connected for simultaneous reciprocating movement therein, means at each end of the said housing for controlling the passage of pressurized hydraulic fluid therethrough for actuation of the pistons, and piston rods projecting in parallel fashion from a common end of the housing, one of said piston rods being in engagement with both of said pistons, and resilient means disposed between the pistons and providing a reaction movement of one piston under power applied against the other, each of said piston rods being adapted for separate connection to a work piece of the press.

References Cited in the file of this patent UNITED STATES PATENTS 546,441 Vogt Sept. 17, 1895 588,600 Pelton Aug. 24, 1897 949,559 Wilson Feb. 15, 1910 1,910,019 Kelly May 23, 1933 2,356,598 Lang Aug. 22, 1944 2,458,900 Erny Jan. 11, 1949 

